1. Field of the Invention
This invention relates in general to connection means for tubular connectors, and in particular to a clamp type connector for use in oil field applications.
2. Description of the Prior Art
Releasable pipe connection joints are used in many oil field applications. Applications include pipes for valve assemblies, wellheads, and other pressure vessels. One type of well known pipe connector is illustrated in U.S. Pat. Nos. 3,216,746, Watts, Nov. 9, 1965 and 3,404,902, R. E. Latham, et al, Oct. 8, 1968. In these connectors, each conduit or pipe has an external flange on its end. The flange is conical in cross-section. The clamp is in two halves. The clamp has mating conical surfaces for clamping the pipe ends together. A T-shaped seal locates between the abutting ends. Bolts draw the clamp together to pre-load the connections.
While these clamp type connectors work well, it would be desirable to reduce the mechanical stresses in the connection. This would enable the clamp connection to be made smaller and lighter.
Also, in drilling and production applications, there are instances where large, heavy conduits must be connected together, and wherein considerable axial distance must be covered during the makeup. This occurs in wellhead housings that locate on top of the well. There are different types of connectors. One type utilizes dogs which are forced into grooves on the wellhead housing profile. The grooves on the profile have conical load shoulders formed at a single angle. In some instances, the dogs may have a lead-in angle formed on the edge to increase the axial drawdown. It is desirable to provide a clamp type connector that would provide a large axial drawdown as the clamp is being made up, then provide a large axial pre-load in the final stages of make up.